wip

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

CODEOWNERS

@@ -498,6 +498,7 @@ esphome/components/voice_assistant/* @jesserockz @kahrendt
 esphome/components/wake_on_lan/* @clydebarrow @willwill2will54
 esphome/components/watchdog/* @oarcher
 esphome/components/waveshare_epaper/* @clydebarrow
+esphome/components/web_server/ota/* @esphome/core
 esphome/components/web_server_base/* @OttoWinter
 esphome/components/web_server_idf/* @dentra
 esphome/components/weikai/* @DrCoolZic

esphome/__main__.py

@@ -458,6 +458,13 @@ def command_vscode(args):
 
 
 def command_compile(args, config):
+    # Set memory analysis options in config
+    if args.analyze_memory:
+        config.setdefault(CONF_ESPHOME, {})["analyze_memory"] = True
+
+    if args.memory_report:
+        config.setdefault(CONF_ESPHOME, {})["memory_report_file"] = args.memory_report
+
     exit_code = write_cpp(config)
     if exit_code != 0:
         return exit_code
@@ -837,6 +844,17 @@ def parse_args(argv):
         help="Only generate source code, do not compile.",
         action="store_true",
     )
+    parser_compile.add_argument(
+        "--analyze-memory",
+        help="Analyze and display memory usage by component after compilation.",
+        action="store_true",
+    )
+    parser_compile.add_argument(
+        "--memory-report",
+        help="Save memory analysis report to a file (supports .json or .txt).",
+        type=str,
+        metavar="FILE",
+    )
 
     parser_upload = subparsers.add_parser(
         "upload",

esphome/components/api/api_connection.cpp

@@ -1687,7 +1687,9 @@ void APIConnection::DeferredBatch::add_item(EntityBase *entity, MessageCreator c
   // O(n) but optimized for RAM and not performance.
   for (auto &item : items) {
     if (item.entity == entity && item.message_type == message_type) {
-      // Update the existing item with the new creator
+      // Clean up old creator before replacing
+      item.creator.cleanup(message_type);
+      // Move assign the new creator
       item.creator = std::move(creator);
       return;
     }
@@ -1730,11 +1732,11 @@ void APIConnection::process_batch_() {
     return;
   }
 
-  size_t num_items = this->deferred_batch_.items.size();
+  size_t num_items = this->deferred_batch_.size();
 
   // Fast path for single message - allocate exact size needed
   if (num_items == 1) {
-    const auto &item = this->deferred_batch_.items[0];
+    const auto &item = this->deferred_batch_[0];
 
     // Let the creator calculate size and encode if it fits
     uint16_t payload_size =
@@ -1764,7 +1766,8 @@ void APIConnection::process_batch_() {
 
   // Pre-calculate exact buffer size needed based on message types
   uint32_t total_estimated_size = 0;
-  for (const auto &item : this->deferred_batch_.items) {
+  for (size_t i = 0; i < this->deferred_batch_.size(); i++) {
+    const auto &item = this->deferred_batch_[i];
     total_estimated_size += get_estimated_message_size(item.message_type);
   }
 
@@ -1785,7 +1788,8 @@ void APIConnection::process_batch_() {
   uint32_t current_offset = 0;
 
   // Process items and encode directly to buffer
-  for (const auto &item : this->deferred_batch_.items) {
+  for (size_t i = 0; i < this->deferred_batch_.size(); i++) {
+    const auto &item = this->deferred_batch_[i];
     // Try to encode message
     // The creator will calculate overhead to determine if the message fits
     uint16_t payload_size = item.creator(item.entity, this, remaining_size, false, item.message_type);
@@ -1840,17 +1844,15 @@ void APIConnection::process_batch_() {
   // Log messages after send attempt for VV debugging
   // It's safe to use the buffer for logging at this point regardless of send result
   for (size_t i = 0; i < items_processed; i++) {
-    const auto &item = this->deferred_batch_.items[i];
+    const auto &item = this->deferred_batch_[i];
     this->log_batch_item_(item);
   }
 #endif
 
   // Handle remaining items more efficiently
-  if (items_processed < this->deferred_batch_.items.size()) {
-    // Remove processed items from the beginning
-    this->deferred_batch_.items.erase(this->deferred_batch_.items.begin(),
-                                      this->deferred_batch_.items.begin() + items_processed);
-
+  if (items_processed < this->deferred_batch_.size()) {
+    // Remove processed items from the beginning with proper cleanup
+    this->deferred_batch_.remove_front(items_processed);
     // Reschedule for remaining items
     this->schedule_batch_();
   } else {
@@ -1861,23 +1863,16 @@ void APIConnection::process_batch_() {
 
 uint16_t APIConnection::MessageCreator::operator()(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,
                                                    bool is_single, uint16_t message_type) const {
-  if (has_tagged_string_ptr_()) {
-    // Handle string-based messages
-    switch (message_type) {
 #ifdef USE_EVENT
-      case EventResponse::MESSAGE_TYPE: {
-        auto *e = static_cast<event::Event *>(entity);
-        return APIConnection::try_send_event_response(e, *get_string_ptr_(), conn, remaining_size, is_single);
-      }
-#endif
-      default:
-        // Should not happen, return 0 to indicate no message
-        return 0;
-    }
-  } else {
-    // Function pointer case
-    return data_.ptr(entity, conn, remaining_size, is_single);
+  // Special case: EventResponse uses string pointer
+  if (message_type == EventResponse::MESSAGE_TYPE) {
+    auto *e = static_cast<event::Event *>(entity);
+    return APIConnection::try_send_event_response(e, *data_.string_ptr, conn, remaining_size, is_single);
   }
+#endif
+
+  // All other message types use function pointers
+  return data_.function_ptr(entity, conn, remaining_size, is_single);
 }
 
 uint16_t APIConnection::try_send_list_info_done(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,

esphome/components/api/api_connection.h

@@ -451,96 +451,53 @@ class APIConnection : public APIServerConnection {
   // Function pointer type for message encoding
   using MessageCreatorPtr = uint16_t (*)(EntityBase *, APIConnection *, uint32_t remaining_size, bool is_single);
 
-  // Optimized MessageCreator class using tagged pointer
   class MessageCreator {
-    // Ensure pointer alignment allows LSB tagging
-    static_assert(alignof(std::string *) > 1, "String pointer alignment must be > 1 for LSB tagging");
-
    public:
     // Constructor for function pointer
-    MessageCreator(MessageCreatorPtr ptr) {
-      // Function pointers are always aligned, so LSB is 0
-      data_.ptr = ptr;
-    }
+    MessageCreator(MessageCreatorPtr ptr) { data_.function_ptr = ptr; }
 
     // Constructor for string state capture
-    explicit MessageCreator(const std::string &str_value) {
-      // Allocate string and tag the pointer
-      auto *str = new std::string(str_value);
-      // Set LSB to 1 to indicate string pointer
-      data_.tagged = reinterpret_cast<uintptr_t>(str) | 1;
-    }
+    explicit MessageCreator(const std::string &str_value) { data_.string_ptr = new std::string(str_value); }
 
-    // Destructor
-    ~MessageCreator() {
-      if (has_tagged_string_ptr_()) {
-        delete get_string_ptr_();
-      }
-    }
+    // No destructor - cleanup must be called explicitly with message_type
 
-    // Copy constructor
-    MessageCreator(const MessageCreator &other) {
-      if (other.has_tagged_string_ptr_()) {
-        auto *str = new std::string(*other.get_string_ptr_());
-        data_.tagged = reinterpret_cast<uintptr_t>(str) | 1;
-      } else {
-        data_ = other.data_;
-      }
-    }
+    // Delete copy operations - MessageCreator should only be moved
+    MessageCreator(const MessageCreator &other) = delete;
+    MessageCreator &operator=(const MessageCreator &other) = delete;
 
     // Move constructor
-    MessageCreator(MessageCreator &&other) noexcept : data_(other.data_) { other.data_.ptr = nullptr; }
-
-    // Assignment operators (needed for batch deduplication)
-    MessageCreator &operator=(const MessageCreator &other) {
-      if (this != &other) {
-        // Clean up current string data if needed
-        if (has_tagged_string_ptr_()) {
-          delete get_string_ptr_();
-        }
-        // Copy new data
-        if (other.has_tagged_string_ptr_()) {
-          auto *str = new std::string(*other.get_string_ptr_());
-          data_.tagged = reinterpret_cast<uintptr_t>(str) | 1;
-        } else {
-          data_ = other.data_;
-        }
-      }
-      return *this;
-    }
+    MessageCreator(MessageCreator &&other) noexcept : data_(other.data_) { other.data_.function_ptr = nullptr; }
 
+    // Move assignment
     MessageCreator &operator=(MessageCreator &&other) noexcept {
       if (this != &other) {
-        // Clean up current string data if needed
-        if (has_tagged_string_ptr_()) {
-          delete get_string_ptr_();
-        }
-        // Move data
+        // IMPORTANT: Caller must ensure cleanup() was called if this contains a string!
+        // In our usage, this happens in add_item() deduplication and vector::erase()
         data_ = other.data_;
-        // Reset other to safe state
-        other.data_.ptr = nullptr;
+        other.data_.function_ptr = nullptr;
       }
       return *this;
     }
 
-    // Call operator - now accepts message_type as parameter
+    // Call operator - uses message_type to determine union type
     uint16_t operator()(EntityBase *entity, APIConnection *conn, uint32_t remaining_size, bool is_single,
                         uint16_t message_type) const;
 
-   private:
-    // Check if this contains a string pointer
-    bool has_tagged_string_ptr_() const { return (data_.tagged & 1) != 0; }
-
-    // Get the actual string pointer (clears the tag bit)
-    std::string *get_string_ptr_() const {
-      // NOLINTNEXTLINE(performance-no-int-to-ptr)
-      return reinterpret_cast<std::string *>(data_.tagged & ~uintptr_t(1));
+    // Manual cleanup method - must be called before destruction for string types
+    void cleanup(uint16_t message_type) {
+#ifdef USE_EVENT
+      if (message_type == EventResponse::MESSAGE_TYPE && data_.string_ptr != nullptr) {
+        delete data_.string_ptr;
+        data_.string_ptr = nullptr;
+      }
+#endif
     }
 
-    union {
-      MessageCreatorPtr ptr;
-      uintptr_t tagged;
-    } data_;  // 4 bytes on 32-bit
+   private:
+    union Data {
+      MessageCreatorPtr function_ptr;
+      std::string *string_ptr;
+    } data_;  // 4 bytes on 32-bit, 8 bytes on 64-bit - same as before
   };
 
   // Generic batching mechanism for both state updates and entity info
@@ -558,20 +515,46 @@ class APIConnection : public APIServerConnection {
     std::vector<BatchItem> items;
     uint32_t batch_start_time{0};
 
+   private:
+    // Helper to cleanup items from the beginning
+    void cleanup_items_(size_t count) {
+      for (size_t i = 0; i < count; i++) {
+        items[i].creator.cleanup(items[i].message_type);
+      }
+    }
+
+   public:
     DeferredBatch() {
       // Pre-allocate capacity for typical batch sizes to avoid reallocation
       items.reserve(8);
     }
 
+    ~DeferredBatch() {
+      // Ensure cleanup of any remaining items
+      clear();
+    }
+
     // Add item to the batch
     void add_item(EntityBase *entity, MessageCreator creator, uint16_t message_type);
     // Add item to the front of the batch (for high priority messages like ping)
     void add_item_front(EntityBase *entity, MessageCreator creator, uint16_t message_type);
+
+    // Clear all items with proper cleanup
     void clear() {
+      cleanup_items_(items.size());
       items.clear();
       batch_start_time = 0;
     }
+
+    // Remove processed items from the front with proper cleanup
+    void remove_front(size_t count) {
+      cleanup_items_(count);
+      items.erase(items.begin(), items.begin() + count);
+    }
+
     bool empty() const { return items.empty(); }
+    size_t size() const { return items.size(); }
+    const BatchItem &operator[](size_t index) const { return items[index]; }
   };
 
   // DeferredBatch here (16 bytes, 4-byte aligned)

esphome/components/api/api_pb2.cpp

@@ -3,6 +3,7 @@
 #include "api_pb2.h"
 #include "api_pb2_size.h"
 #include "esphome/core/log.h"
+#include "esphome/core/helpers.h"
 
 #include <cinttypes>
 
@@ -3510,7 +3511,7 @@ void SubscribeLogsResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  message: ");
-  out.append("'").append(this->message).append("'");
+  out.append(format_hex_pretty(this->message));
   out.append("\n");
 
   out.append("  send_failed: ");
@@ -3538,7 +3539,7 @@ void NoiseEncryptionSetKeyRequest::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("NoiseEncryptionSetKeyRequest {\n");
   out.append("  key: ");
-  out.append("'").append(this->key).append("'");
+  out.append(format_hex_pretty(this->key));
   out.append("\n");
   out.append("}");
 }
@@ -4284,7 +4285,7 @@ void CameraImageResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
 
   out.append("  done: ");
@@ -6811,7 +6812,7 @@ void BluetoothServiceData::dump_to(std::string &out) const {
   }
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
   out.append("}");
 }
@@ -6894,7 +6895,7 @@ void BluetoothLEAdvertisementResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  name: ");
-  out.append("'").append(this->name).append("'");
+  out.append(format_hex_pretty(this->name));
   out.append("\n");
 
   out.append("  rssi: ");
@@ -6987,7 +6988,7 @@ void BluetoothLERawAdvertisement::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
   out.append("}");
 }
@@ -7514,7 +7515,7 @@ void BluetoothGATTReadResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
   out.append("}");
 }
@@ -7578,7 +7579,7 @@ void BluetoothGATTWriteRequest::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
   out.append("}");
 }
@@ -7670,7 +7671,7 @@ void BluetoothGATTWriteDescriptorRequest::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
   out.append("}");
 }
@@ -7772,7 +7773,7 @@ void BluetoothGATTNotifyDataResponse::dump_to(std::string &out) const {
   out.append("\n");
 
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
   out.append("}");
 }
@@ -8492,7 +8493,7 @@ void VoiceAssistantAudio::dump_to(std::string &out) const {
   __attribute__((unused)) char buffer[64];
   out.append("VoiceAssistantAudio {\n");
   out.append("  data: ");
-  out.append("'").append(this->data).append("'");
+  out.append(format_hex_pretty(this->data));
   out.append("\n");
 
   out.append("  end: ");

esphome/components/captive_portal/__init__.py

@@ -12,7 +12,7 @@ from esphome.const import (
 )
 from esphome.core import CORE, coroutine_with_priority
 
-AUTO_LOAD = ["web_server_base"]
+AUTO_LOAD = ["web_server_base", "ota.web_server"]
 DEPENDENCIES = ["wifi"]
 CODEOWNERS = ["@OttoWinter"]
 

esphome/components/captive_portal/captive_portal.cpp

@@ -47,9 +47,6 @@ void CaptivePortal::start() {
   this->base_->init();
   if (!this->initialized_) {
     this->base_->add_handler(this);
-#ifdef USE_WEBSERVER_OTA
-    this->base_->add_ota_handler();
-#endif
   }
 
 #ifdef USE_ARDUINO

esphome/components/esp32_rmt_led_strip/led_strip.cpp

@@ -21,6 +21,43 @@ static const uint32_t RMT_CLK_FREQ = 80000000;
 static const uint8_t RMT_CLK_DIV = 2;
 #endif
 
+static const size_t RMT_SYMBOLS_PER_BYTE = 8;
+
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
+static size_t IRAM_ATTR HOT encoder_callback(const void *data, size_t size, size_t symbols_written, size_t symbols_free,
+                                             rmt_symbol_word_t *symbols, bool *done, void *arg) {
+  auto *params = static_cast<LedParams *>(arg);
+  const auto *bytes = static_cast<const uint8_t *>(data);
+  size_t index = symbols_written / RMT_SYMBOLS_PER_BYTE;
+
+  // convert byte to symbols
+  if (index < size) {
+    if (symbols_free < RMT_SYMBOLS_PER_BYTE) {
+      return 0;
+    }
+    for (int32_t i = 0; i < RMT_SYMBOLS_PER_BYTE; i++) {
+      if (bytes[index] & (1 << (7 - i))) {
+        symbols[i] = params->bit1;
+      } else {
+        symbols[i] = params->bit0;
+      }
+    }
+    if ((index + 1) >= size && params->reset.duration0 == 0 && params->reset.duration1 == 0) {
+      *done = true;
+    }
+    return RMT_SYMBOLS_PER_BYTE;
+  }
+
+  // send reset
+  if (symbols_free < 1) {
+    return 0;
+  }
+  symbols[0] = params->reset;
+  *done = true;
+  return 1;
+}
+#endif
+
 void ESP32RMTLEDStripLightOutput::setup() {
   ESP_LOGCONFIG(TAG, "Running setup");
 
@@ -42,10 +79,15 @@ void ESP32RMTLEDStripLightOutput::setup() {
     return;
   }
 
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
+  // copy of the led buffer
+  this->rmt_buf_ = allocator.allocate(buffer_size);
+#else
   RAMAllocator<rmt_symbol_word_t> rmt_allocator(this->use_psram_ ? 0 : RAMAllocator<rmt_symbol_word_t>::ALLOC_INTERNAL);
 
   // 8 bits per byte, 1 rmt_symbol_word_t per bit + 1 rmt_symbol_word_t for reset
   this->rmt_buf_ = rmt_allocator.allocate(buffer_size * 8 + 1);
+#endif
 
   rmt_tx_channel_config_t channel;
   memset(&channel, 0, sizeof(channel));
@@ -65,6 +107,18 @@ void ESP32RMTLEDStripLightOutput::setup() {
     return;
   }
 
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
+  rmt_simple_encoder_config_t encoder;
+  memset(&encoder, 0, sizeof(encoder));
+  encoder.callback = encoder_callback;
+  encoder.arg = &this->params_;
+  encoder.min_chunk_size = 8;
+  if (rmt_new_simple_encoder(&encoder, &this->encoder_) != ESP_OK) {
+    ESP_LOGE(TAG, "Encoder creation failed");
+    this->mark_failed();
+    return;
+  }
+#else
   rmt_copy_encoder_config_t encoder;
   memset(&encoder, 0, sizeof(encoder));
   if (rmt_new_copy_encoder(&encoder, &this->encoder_) != ESP_OK) {
@@ -72,6 +126,7 @@ void ESP32RMTLEDStripLightOutput::setup() {
     this->mark_failed();
     return;
   }
+#endif
 
   if (rmt_enable(this->channel_) != ESP_OK) {
     ESP_LOGE(TAG, "Enabling channel failed");
@@ -85,20 +140,20 @@ void ESP32RMTLEDStripLightOutput::set_led_params(uint32_t bit0_high, uint32_t bi
   float ratio = (float) RMT_CLK_FREQ / RMT_CLK_DIV / 1e09f;
 
   // 0-bit
-  this->bit0_.duration0 = (uint32_t) (ratio * bit0_high);
-  this->bit0_.level0 = 1;
-  this->bit0_.duration1 = (uint32_t) (ratio * bit0_low);
-  this->bit0_.level1 = 0;
+  this->params_.bit0.duration0 = (uint32_t) (ratio * bit0_high);
+  this->params_.bit0.level0 = 1;
+  this->params_.bit0.duration1 = (uint32_t) (ratio * bit0_low);
+  this->params_.bit0.level1 = 0;
   // 1-bit
-  this->bit1_.duration0 = (uint32_t) (ratio * bit1_high);
-  this->bit1_.level0 = 1;
-  this->bit1_.duration1 = (uint32_t) (ratio * bit1_low);
-  this->bit1_.level1 = 0;
+  this->params_.bit1.duration0 = (uint32_t) (ratio * bit1_high);
+  this->params_.bit1.level0 = 1;
+  this->params_.bit1.duration1 = (uint32_t) (ratio * bit1_low);
+  this->params_.bit1.level1 = 0;
   // reset
-  this->reset_.duration0 = (uint32_t) (ratio * reset_time_high);
-  this->reset_.level0 = 1;
-  this->reset_.duration1 = (uint32_t) (ratio * reset_time_low);
-  this->reset_.level1 = 0;
+  this->params_.reset.duration0 = (uint32_t) (ratio * reset_time_high);
+  this->params_.reset.level0 = 1;
+  this->params_.reset.duration1 = (uint32_t) (ratio * reset_time_low);
+  this->params_.reset.level1 = 0;
 }
 
 void ESP32RMTLEDStripLightOutput::write_state(light::LightState *state) {
@@ -122,6 +177,9 @@ void ESP32RMTLEDStripLightOutput::write_state(light::LightState *state) {
   }
   delayMicroseconds(50);
 
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
+  memcpy(this->rmt_buf_, this->buf_, this->get_buffer_size_());
+#else
   size_t buffer_size = this->get_buffer_size_();
 
   size_t size = 0;
@@ -131,7 +189,7 @@ void ESP32RMTLEDStripLightOutput::write_state(light::LightState *state) {
   while (size < buffer_size) {
     uint8_t b = *psrc;
     for (int i = 0; i < 8; i++) {
-      pdest->val = b & (1 << (7 - i)) ? this->bit1_.val : this->bit0_.val;
+      pdest->val = b & (1 << (7 - i)) ? this->params_.bit1.val : this->params_.bit0.val;
       pdest++;
       len++;
     }
@@ -139,17 +197,20 @@ void ESP32RMTLEDStripLightOutput::write_state(light::LightState *state) {
     psrc++;
   }
 
-  if (this->reset_.duration0 > 0 || this->reset_.duration1 > 0) {
-    pdest->val = this->reset_.val;
+  if (this->params_.reset.duration0 > 0 || this->params_.reset.duration1 > 0) {
+    pdest->val = this->params_.reset.val;
     pdest++;
     len++;
   }
+#endif
 
   rmt_transmit_config_t config;
   memset(&config, 0, sizeof(config));
-  config.loop_count = 0;
-  config.flags.eot_level = 0;
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
+  error = rmt_transmit(this->channel_, this->encoder_, this->rmt_buf_, this->get_buffer_size_(), &config);
+#else
   error = rmt_transmit(this->channel_, this->encoder_, this->rmt_buf_, len * sizeof(rmt_symbol_word_t), &config);
+#endif
   if (error != ESP_OK) {
     ESP_LOGE(TAG, "RMT TX error");
     this->status_set_warning();

esphome/components/esp32_rmt_led_strip/led_strip.h

@@ -25,6 +25,12 @@ enum RGBOrder : uint8_t {
   ORDER_BRG,
 };
 
+struct LedParams {
+  rmt_symbol_word_t bit0;
+  rmt_symbol_word_t bit1;
+  rmt_symbol_word_t reset;
+};
+
 class ESP32RMTLEDStripLightOutput : public light::AddressableLight {
  public:
   void setup() override;
@@ -72,12 +78,15 @@ class ESP32RMTLEDStripLightOutput : public light::AddressableLight {
 
   uint8_t *buf_{nullptr};
   uint8_t *effect_data_{nullptr};
+  LedParams params_;
   rmt_channel_handle_t channel_{nullptr};
   rmt_encoder_handle_t encoder_{nullptr};
+#if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 3, 0)
+  uint8_t *rmt_buf_{nullptr};
+#else
   rmt_symbol_word_t *rmt_buf_{nullptr};
-  rmt_symbol_word_t bit0_, bit1_, reset_;
+#endif
   uint32_t rmt_symbols_{48};
-
   uint8_t pin_;
   uint16_t num_leds_;
   bool is_rgbw_{false};

esphome/components/http_request/http_request_arduino.cpp

@@ -133,7 +133,6 @@ std::shared_ptr<HttpContainer> HttpRequestArduino::perform(std::string url, std:
       std::string header_value = container->client_.header(i).c_str();
       ESP_LOGD(TAG, "Received response header, name: %s, value: %s", header_name.c_str(), header_value.c_str());
       container->response_headers_[header_name].push_back(header_value);
-      break;
     }
   }
 

esphome/components/http_request/http_request_idf.cpp

@@ -42,7 +42,6 @@ esp_err_t HttpRequestIDF::http_event_handler(esp_http_client_event_t *evt) {
         const std::string header_value = evt->header_value;
         ESP_LOGD(TAG, "Received response header, name: %s, value: %s", header_name.c_str(), header_value.c_str());
         user_data->response_headers[header_name].push_back(header_value);
-        break;
       }
       break;
     }

esphome/components/mmc5603/mmc5603.cpp

@@ -39,7 +39,7 @@ void MMC5603Component::setup() {
     return;
   }
 
-  if (id != MMC56X3_CHIP_ID) {
+  if (id != 0 && id != MMC56X3_CHIP_ID) {  // ID is not reported correctly by all chips, 0 on some chips
     ESP_LOGCONFIG(TAG, "Chip Wrong");
     this->error_code_ = ID_REGISTERS;
     this->mark_failed();

esphome/components/nextion/nextion.cpp

@@ -164,7 +164,7 @@ void Nextion::dump_config() {
 #endif  // USE_NEXTION_MAX_COMMANDS_PER_LOOP
 
   if (this->touch_sleep_timeout_ != 0) {
-    ESP_LOGCONFIG(TAG, "  Touch Timeout:  %" PRIu32, this->touch_sleep_timeout_);
+    ESP_LOGCONFIG(TAG, "  Touch Timeout:  %" PRIu16, this->touch_sleep_timeout_);
   }
 
   if (this->wake_up_page_ != -1) {
@@ -302,11 +302,11 @@ void Nextion::loop() {
     }
 
     // Check if a startup page has been set and send the command
-    if (this->start_up_page_ != -1) {
+    if (this->start_up_page_ >= 0) {
       this->goto_page(this->start_up_page_);
     }
 
-    if (this->wake_up_page_ != -1) {
+    if (this->wake_up_page_ >= 0) {
       this->set_wake_up_page(this->wake_up_page_);
     }
 
@@ -418,12 +418,12 @@ void Nextion::process_nextion_commands_() {
       ESP_LOGN(TAG, "Add 0xFF");
     }
 
-    this->nextion_event_ = this->command_data_[0];
+    const uint8_t nextion_event = this->command_data_[0];
 
     to_process_length -= 1;
     to_process = this->command_data_.substr(1, to_process_length);
 
-    switch (this->nextion_event_) {
+    switch (nextion_event) {
       case 0x00:  // instruction sent by user has failed
         ESP_LOGW(TAG, "Invalid instruction");
         this->remove_from_q_();
@@ -562,9 +562,9 @@ void Nextion::process_nextion_commands_() {
           break;
         }
 
-        uint16_t x = (uint16_t(to_process[0]) << 8) | to_process[1];
-        uint16_t y = (uint16_t(to_process[2]) << 8) | to_process[3];
-        uint8_t touch_event = to_process[4];  // 0 -> release, 1 -> press
+        const uint16_t x = (uint16_t(to_process[0]) << 8) | to_process[1];
+        const uint16_t y = (uint16_t(to_process[2]) << 8) | to_process[3];
+        const uint8_t touch_event = to_process[4];  // 0 -> release, 1 -> press
         ESP_LOGD(TAG, "Touch %s at %u,%u", touch_event ? "PRESS" : "RELEASE", x, y);
         break;
       }
@@ -820,15 +820,14 @@ void Nextion::process_nextion_commands_() {
         break;
       }
       default:
-        ESP_LOGW(TAG, "Unknown event: 0x%02X", this->nextion_event_);
+        ESP_LOGW(TAG, "Unknown event: 0x%02X", nextion_event);
         break;
     }
 
-    // ESP_LOGN(TAG, "nextion_event_ deleting from 0 to %d", to_process_length + COMMAND_DELIMITER.length() + 1);
     this->command_data_.erase(0, to_process_length + COMMAND_DELIMITER.length() + 1);
   }
 
-  uint32_t ms = App.get_loop_component_start_time();
+  const uint32_t ms = App.get_loop_component_start_time();
 
   if (!this->nextion_queue_.empty() && this->nextion_queue_.front()->queue_time + this->max_q_age_ms_ < ms) {
     for (size_t i = 0; i < this->nextion_queue_.size(); i++) {
@@ -960,7 +959,6 @@ void Nextion::update_components_by_prefix(const std::string &prefix) {
 }
 
 uint16_t Nextion::recv_ret_string_(std::string &response, uint32_t timeout, bool recv_flag) {
-  uint16_t ret = 0;
   uint8_t c = 0;
   uint8_t nr_of_ff_bytes = 0;
   bool exit_flag = false;
@@ -1003,8 +1001,7 @@ uint16_t Nextion::recv_ret_string_(std::string &response, uint32_t timeout, bool
   if (ff_flag)
     response = response.substr(0, response.length() - 3);  // Remove last 3 0xFF
 
-  ret = response.length();
-  return ret;
+  return response.length();
 }
 
 /**

esphome/components/nextion/nextion.h

@@ -1190,11 +1190,11 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
    * After 30 seconds the display will go to sleep. Note: the display will only wakeup by a restart or by setting up
    * `thup`.
    */
-  void set_touch_sleep_timeout(uint32_t touch_sleep_timeout);
+  void set_touch_sleep_timeout(uint16_t touch_sleep_timeout);
 
   /**
    * Sets which page Nextion loads when exiting sleep mode. Note this can be set even when Nextion is in sleep mode.
-   * @param wake_up_page The page id, from 0 to the lage page in Nextion. Set 255 (not set to any existing page) to
+   * @param wake_up_page The page id, from 0 to the last page in Nextion. Set -1 (not set to any existing page) to
    * wakes up to current page.
    *
    * Example:
@@ -1204,11 +1204,11 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
    *
    * The display will wake up to page 2.
    */
-  void set_wake_up_page(uint8_t wake_up_page = 255);
+  void set_wake_up_page(int16_t wake_up_page = -1);
 
   /**
    * Sets which page Nextion loads when connecting to ESPHome.
-   * @param start_up_page The page id, from 0 to the lage page in Nextion. Set 255 (not set to any existing page) to
+   * @param start_up_page The page id, from 0 to the last page in Nextion. Set -1 (not set to any existing page) to
    * wakes up to current page.
    *
    * Example:
@@ -1218,7 +1218,7 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
    *
    * The display will go to page 2 when it establishes a connection to ESPHome.
    */
-  void set_start_up_page(uint8_t start_up_page = 255) { this->start_up_page_ = start_up_page; }
+  void set_start_up_page(int16_t start_up_page = -1) { this->start_up_page_ = start_up_page; }
 
   /**
    * Sets if Nextion should auto-wake from sleep when touch press occurs.
@@ -1330,7 +1330,7 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
   std::deque<NextionQueue *> waveform_queue_;
   uint16_t recv_ret_string_(std::string &response, uint32_t timeout, bool recv_flag);
   void all_components_send_state_(bool force_update = false);
-  uint64_t comok_sent_ = 0;
+  uint32_t comok_sent_ = 0;
   bool remove_from_q_(bool report_empty = true);
 
   /**
@@ -1340,12 +1340,10 @@ class Nextion : public NextionBase, public PollingComponent, public uart::UARTDe
   bool ignore_is_setup_ = false;
 
   bool nextion_reports_is_setup_ = false;
-  uint8_t nextion_event_;
-
   void process_nextion_commands_();
   void process_serial_();
   bool is_updating_ = false;
-  uint32_t touch_sleep_timeout_ = 0;
+  uint16_t touch_sleep_timeout_ = 0;
   int16_t wake_up_page_ = -1;
   int16_t start_up_page_ = -1;
   bool auto_wake_on_touch_ = true;

esphome/components/nextion/nextion_commands.cpp

@@ -10,12 +10,12 @@ static const char *const TAG = "nextion";
 // Sleep safe commands
 void Nextion::soft_reset() { this->send_command_("rest"); }
 
-void Nextion::set_wake_up_page(uint8_t wake_up_page) {
+void Nextion::set_wake_up_page(int16_t wake_up_page) {
   this->wake_up_page_ = wake_up_page;
   this->add_no_result_to_queue_with_set_internal_("wake_up_page", "wup", wake_up_page, true);
 }
 
-void Nextion::set_touch_sleep_timeout(uint32_t touch_sleep_timeout) {
+void Nextion::set_touch_sleep_timeout(uint16_t touch_sleep_timeout) {
   if (touch_sleep_timeout < 3) {
     ESP_LOGD(TAG, "Sleep timeout out of bounds (3-65535)");
     return;

esphome/components/ota/ota_backend.h

@@ -67,7 +67,28 @@ class OTAComponent : public Component {
   }
 
  protected:
-  CallbackManager<void(ota::OTAState, float, uint8_t)> state_callback_{};
+  /** Extended callback manager with deferred call support.
+   *
+   * This adds a call_deferred() method for thread-safe execution from other tasks.
+   */
+  class StateCallbackManager : public CallbackManager<void(OTAState, float, uint8_t)> {
+   public:
+    StateCallbackManager(OTAComponent *component) : component_(component) {}
+
+    /** Call callbacks with deferral to main loop (for thread safety).
+     *
+     * This should be used by OTA implementations that run in separate tasks
+     * (like web_server OTA) to ensure callbacks execute in the main loop.
+     */
+    void call_deferred(ota::OTAState state, float progress, uint8_t error) {
+      component_->defer([this, state, progress, error]() { this->call(state, progress, error); });
+    }
+
+   private:
+    OTAComponent *component_;
+  };
+
+  StateCallbackManager state_callback_{this};
 #endif
 };
 
@@ -89,6 +110,11 @@ class OTAGlobalCallback {
 
 OTAGlobalCallback *get_global_ota_callback();
 void register_ota_platform(OTAComponent *ota_caller);
+
+// OTA implementations should use:
+// - state_callback_.call() when already in main loop (e.g., esphome OTA)
+// - state_callback_.call_deferred() when in separate task (e.g., web_server OTA)
+// This ensures proper callback execution in all contexts.
 #endif
 std::unique_ptr<ota::OTABackend> make_ota_backend();
 

esphome/components/ota/ota_backend_arduino_esp32.cpp

@@ -15,6 +15,11 @@ static const char *const TAG = "ota.arduino_esp32";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoESP32OTABackend>(); }
 
 OTAResponseTypes ArduinoESP32OTABackend::begin(size_t image_size) {
+  // Handle UPDATE_SIZE_UNKNOWN (0) which is used by web server OTA
+  // where the exact firmware size is unknown due to multipart encoding
+  if (image_size == 0) {
+    image_size = UPDATE_SIZE_UNKNOWN;
+  }
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     return OTA_RESPONSE_OK;
@@ -29,7 +34,10 @@ OTAResponseTypes ArduinoESP32OTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoESP32OTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoESP32OTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoESP32OTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -44,7 +52,9 @@ OTAResponseTypes ArduinoESP32OTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoESP32OTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  if (Update.end(!this->md5_set_)) {
     return OTA_RESPONSE_OK;
   }
 

esphome/components/ota/ota_backend_arduino_esp32.h

@@ -16,6 +16,9 @@ class ArduinoESP32OTABackend : public OTABackend {
   OTAResponseTypes end() override;
   void abort() override;
   bool supports_compression() override { return false; }
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_arduino_esp8266.cpp

@@ -17,6 +17,11 @@ static const char *const TAG = "ota.arduino_esp8266";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoESP8266OTABackend>(); }
 
 OTAResponseTypes ArduinoESP8266OTABackend::begin(size_t image_size) {
+  // Handle UPDATE_SIZE_UNKNOWN (0) by calculating available space
+  if (image_size == 0) {
+    // NOLINTNEXTLINE(readability-static-accessed-through-instance)
+    image_size = (ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000;
+  }
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     esp8266::preferences_prevent_write(true);
@@ -38,7 +43,10 @@ OTAResponseTypes ArduinoESP8266OTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoESP8266OTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoESP8266OTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoESP8266OTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -53,13 +61,19 @@ OTAResponseTypes ArduinoESP8266OTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoESP8266OTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  bool success = Update.end(!this->md5_set_);
+
+  // On ESP8266, Update.end() might return false even with error code 0
+  // Check the actual error code to determine success
+  uint8_t error = Update.getError();
+
+  if (success || error == UPDATE_ERROR_OK) {
     return OTA_RESPONSE_OK;
   }
 
-  uint8_t error = Update.getError();
   ESP_LOGE(TAG, "End error: %d", error);
-
   return OTA_RESPONSE_ERROR_UPDATE_END;
 }
 

esphome/components/ota/ota_backend_arduino_esp8266.h

@@ -21,6 +21,9 @@ class ArduinoESP8266OTABackend : public OTABackend {
 #else
   bool supports_compression() override { return false; }
 #endif
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_arduino_libretiny.cpp

@@ -15,6 +15,11 @@ static const char *const TAG = "ota.arduino_libretiny";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoLibreTinyOTABackend>(); }
 
 OTAResponseTypes ArduinoLibreTinyOTABackend::begin(size_t image_size) {
+  // Handle UPDATE_SIZE_UNKNOWN (0) which is used by web server OTA
+  // where the exact firmware size is unknown due to multipart encoding
+  if (image_size == 0) {
+    image_size = UPDATE_SIZE_UNKNOWN;
+  }
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     return OTA_RESPONSE_OK;
@@ -29,7 +34,10 @@ OTAResponseTypes ArduinoLibreTinyOTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoLibreTinyOTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoLibreTinyOTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoLibreTinyOTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -44,7 +52,9 @@ OTAResponseTypes ArduinoLibreTinyOTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoLibreTinyOTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  if (Update.end(!this->md5_set_)) {
     return OTA_RESPONSE_OK;
   }
 

esphome/components/ota/ota_backend_arduino_libretiny.h

@@ -15,6 +15,9 @@ class ArduinoLibreTinyOTABackend : public OTABackend {
   OTAResponseTypes end() override;
   void abort() override;
   bool supports_compression() override { return false; }
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_arduino_rp2040.cpp

@@ -17,6 +17,8 @@ static const char *const TAG = "ota.arduino_rp2040";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoRP2040OTABackend>(); }
 
 OTAResponseTypes ArduinoRP2040OTABackend::begin(size_t image_size) {
+  // OTA size of 0 is not currently handled, but
+  // web_server is not supported for RP2040, so this is not an issue.
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     rp2040::preferences_prevent_write(true);
@@ -38,7 +40,10 @@ OTAResponseTypes ArduinoRP2040OTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoRP2040OTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoRP2040OTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoRP2040OTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -53,7 +58,9 @@ OTAResponseTypes ArduinoRP2040OTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoRP2040OTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  if (Update.end(!this->md5_set_)) {
     return OTA_RESPONSE_OK;
   }
 

esphome/components/ota/ota_backend_arduino_rp2040.h

@@ -17,6 +17,9 @@ class ArduinoRP2040OTABackend : public OTABackend {
   OTAResponseTypes end() override;
   void abort() override;
   bool supports_compression() override { return false; }
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_esp_idf.cpp

@@ -56,7 +56,10 @@ OTAResponseTypes IDFOTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_OK;
 }
 
-void IDFOTABackend::set_update_md5(const char *expected_md5) { memcpy(this->expected_bin_md5_, expected_md5, 32); }
+void IDFOTABackend::set_update_md5(const char *expected_md5) {
+  memcpy(this->expected_bin_md5_, expected_md5, 32);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes IDFOTABackend::write(uint8_t *data, size_t len) {
   esp_err_t err = esp_ota_write(this->update_handle_, data, len);
@@ -73,10 +76,12 @@ OTAResponseTypes IDFOTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes IDFOTABackend::end() {
-  this->md5_.calculate();
-  if (!this->md5_.equals_hex(this->expected_bin_md5_)) {
-    this->abort();
-    return OTA_RESPONSE_ERROR_MD5_MISMATCH;
+  if (this->md5_set_) {
+    this->md5_.calculate();
+    if (!this->md5_.equals_hex(this->expected_bin_md5_)) {
+      this->abort();
+      return OTA_RESPONSE_ERROR_MD5_MISMATCH;
+    }
   }
   esp_err_t err = esp_ota_end(this->update_handle_);
   this->update_handle_ = 0;

esphome/components/ota/ota_backend_esp_idf.h

@@ -24,6 +24,7 @@ class IDFOTABackend : public OTABackend {
   const esp_partition_t *partition_;
   md5::MD5Digest md5_{};
   char expected_bin_md5_[32];
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/pulse_meter/pulse_meter_sensor.cpp

@@ -31,6 +31,10 @@ void PulseMeterSensor::setup() {
     this->pulse_state_.latched_ = this->last_pin_val_;
     this->pin_->attach_interrupt(PulseMeterSensor::pulse_intr, this, gpio::INTERRUPT_ANY_EDGE);
   }
+
+  if (this->total_sensor_ != nullptr) {
+    this->total_sensor_->publish_state(this->total_pulses_);
+  }
 }
 
 void PulseMeterSensor::loop() {

esphome/components/qr_code/__init__.py

@@ -21,21 +21,24 @@ ECC = {
     "HIGH": qrcodegen_Ecc.qrcodegen_Ecc_HIGH,
 }
 
-CONFIG_SCHEMA = cv.Schema(
-    {
-        cv.Required(CONF_ID): cv.declare_id(QRCode),
-        cv.Required(CONF_VALUE): cv.string,
-        cv.Optional(CONF_ECC, default="LOW"): cv.enum(ECC, upper=True),
-    }
+CONFIG_SCHEMA = cv.ensure_list(
+    cv.Schema(
+        {
+            cv.Required(CONF_ID): cv.declare_id(QRCode),
+            cv.Required(CONF_VALUE): cv.string,
+            cv.Optional(CONF_ECC, default="LOW"): cv.enum(ECC, upper=True),
+        }
+    )
 )
 
 
 async def to_code(config):
     cg.add_library("wjtje/qr-code-generator-library", "^1.7.0")
 
-    var = cg.new_Pvariable(config[CONF_ID])
-    cg.add(var.set_value(config[CONF_VALUE]))
-    cg.add(var.set_ecc(ECC[config[CONF_ECC]]))
-    await cg.register_component(var, config)
+    for entry in config:
+        var = cg.new_Pvariable(entry[CONF_ID])
+        cg.add(var.set_value(entry[CONF_VALUE]))
+        cg.add(var.set_ecc(ECC[entry[CONF_ECC]]))
+        await cg.register_component(var, entry)
 
     cg.add_define("USE_QR_CODE")

esphome/components/web_server/__init__.py

@@ -33,6 +33,7 @@ from esphome.const import (
 )
 from esphome.core import CORE, coroutine_with_priority
 import esphome.final_validate as fv
+from esphome.types import ConfigType
 
 AUTO_LOAD = ["json", "web_server_base"]
 
@@ -47,7 +48,7 @@ WebServer = web_server_ns.class_("WebServer", cg.Component, cg.Controller)
 sorting_groups = {}
 
 
-def default_url(config):
+def default_url(config: ConfigType) -> ConfigType:
     config = config.copy()
     if config[CONF_VERSION] == 1:
         if CONF_CSS_URL not in config:
@@ -67,13 +68,27 @@ def default_url(config):
     return config
 
 
-def validate_local(config):
+def validate_local(config: ConfigType) -> ConfigType:
     if CONF_LOCAL in config and config[CONF_VERSION] == 1:
         raise cv.Invalid("'local' is not supported in version 1")
     return config
 
 
-def validate_sorting_groups(config):
+def validate_ota_removed(config: ConfigType) -> ConfigType:
+    # Only raise error if OTA is explicitly enabled (True)
+    # If it's False or not specified, we can safely ignore it
+    if config.get(CONF_OTA):
+        raise cv.Invalid(
+            f"The '{CONF_OTA}' option has been removed from 'web_server'. "
+            f"Please use the new OTA platform structure instead:\n\n"
+            f"ota:\n"
+            f"  - platform: web_server\n\n"
+            f"See https://esphome.io/components/ota for more information."
+        )
+    return config
+
+
+def validate_sorting_groups(config: ConfigType) -> ConfigType:
     if CONF_SORTING_GROUPS in config and config[CONF_VERSION] != 3:
         raise cv.Invalid(
             f"'{CONF_SORTING_GROUPS}' is only supported in 'web_server' version 3"
@@ -84,7 +99,7 @@ def validate_sorting_groups(config):
 def _validate_no_sorting_component(
     sorting_component: str,
     webserver_version: int,
-    config: dict,
+    config: ConfigType,
     path: list[str] | None = None,
 ) -> None:
     if path is None:
@@ -107,7 +122,7 @@ def _validate_no_sorting_component(
                     )
 
 
-def _final_validate_sorting(config):
+def _final_validate_sorting(config: ConfigType) -> ConfigType:
     if (webserver_version := config.get(CONF_VERSION)) != 3:
         _validate_no_sorting_component(
             CONF_SORTING_WEIGHT, webserver_version, fv.full_config.get()
@@ -170,7 +185,7 @@ CONFIG_SCHEMA = cv.All(
                 web_server_base.WebServerBase
             ),
             cv.Optional(CONF_INCLUDE_INTERNAL, default=False): cv.boolean,
-            cv.Optional(CONF_OTA, default=True): cv.boolean,
+            cv.Optional(CONF_OTA, default=False): cv.boolean,
             cv.Optional(CONF_LOG, default=True): cv.boolean,
             cv.Optional(CONF_LOCAL): cv.boolean,
             cv.Optional(CONF_SORTING_GROUPS): cv.ensure_list(sorting_group),
@@ -188,6 +203,7 @@ CONFIG_SCHEMA = cv.All(
     default_url,
     validate_local,
     validate_sorting_groups,
+    validate_ota_removed,
 )
 
 
@@ -271,11 +287,8 @@ async def to_code(config):
     else:
         cg.add(var.set_css_url(config[CONF_CSS_URL]))
         cg.add(var.set_js_url(config[CONF_JS_URL]))
-    cg.add(var.set_allow_ota(config[CONF_OTA]))
-    if config[CONF_OTA]:
-        # Define USE_WEBSERVER_OTA based only on web_server OTA config
-        # This allows web server OTA to work without loading the OTA component
-        cg.add_define("USE_WEBSERVER_OTA")
+    # OTA is now handled by the web_server OTA platform
+    # The CONF_OTA option is kept only for backwards compatibility validation
     cg.add(var.set_expose_log(config[CONF_LOG]))
     if config[CONF_ENABLE_PRIVATE_NETWORK_ACCESS]:
         cg.add_define("USE_WEBSERVER_PRIVATE_NETWORK_ACCESS")

esphome/components/web_server/ota/__init__.py

@@ -0,0 +1,32 @@
+import esphome.codegen as cg
+from esphome.components.esp32 import add_idf_component
+from esphome.components.ota import BASE_OTA_SCHEMA, OTAComponent, ota_to_code
+import esphome.config_validation as cv
+from esphome.const import CONF_ID
+from esphome.core import CORE, coroutine_with_priority
+
+CODEOWNERS = ["@esphome/core"]
+DEPENDENCIES = ["network", "web_server_base"]
+
+web_server_ns = cg.esphome_ns.namespace("web_server")
+WebServerOTAComponent = web_server_ns.class_("WebServerOTAComponent", OTAComponent)
+
+CONFIG_SCHEMA = (
+    cv.Schema(
+        {
+            cv.GenerateID(): cv.declare_id(WebServerOTAComponent),
+        }
+    )
+    .extend(BASE_OTA_SCHEMA)
+    .extend(cv.COMPONENT_SCHEMA)
+)
+
+
+@coroutine_with_priority(52.0)
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID])
+    await ota_to_code(var, config)
+    await cg.register_component(var, config)
+    cg.add_define("USE_WEBSERVER_OTA")
+    if CORE.using_esp_idf:
+        add_idf_component(name="zorxx/multipart-parser", ref="1.0.1")

esphome/components/web_server/ota/ota_web_server.cpp

@@ -0,0 +1,210 @@
+#include "ota_web_server.h"
+#ifdef USE_WEBSERVER_OTA
+
+#include "esphome/components/ota/ota_backend.h"
+#include "esphome/core/application.h"
+#include "esphome/core/log.h"
+
+#ifdef USE_ARDUINO
+#ifdef USE_ESP8266
+#include <Updater.h>
+#elif defined(USE_ESP32) || defined(USE_LIBRETINY)
+#include <Update.h>
+#endif
+#endif  // USE_ARDUINO
+
+namespace esphome {
+namespace web_server {
+
+static const char *const TAG = "web_server.ota";
+
+class OTARequestHandler : public AsyncWebHandler {
+ public:
+  OTARequestHandler(WebServerOTAComponent *parent) : parent_(parent) {}
+  void handleRequest(AsyncWebServerRequest *request) override;
+  void handleUpload(AsyncWebServerRequest *request, const String &filename, size_t index, uint8_t *data, size_t len,
+                    bool final) override;
+  bool canHandle(AsyncWebServerRequest *request) const override {
+    return request->url() == "/update" && request->method() == HTTP_POST;
+  }
+
+  // NOLINTNEXTLINE(readability-identifier-naming)
+  bool isRequestHandlerTrivial() const override { return false; }
+
+ protected:
+  void report_ota_progress_(AsyncWebServerRequest *request);
+  void schedule_ota_reboot_();
+  void ota_init_(const char *filename);
+
+  uint32_t last_ota_progress_{0};
+  uint32_t ota_read_length_{0};
+  WebServerOTAComponent *parent_;
+  bool ota_success_{false};
+
+ private:
+  std::unique_ptr<ota::OTABackend> ota_backend_{nullptr};
+};
+
+void OTARequestHandler::report_ota_progress_(AsyncWebServerRequest *request) {
+  const uint32_t now = millis();
+  if (now - this->last_ota_progress_ > 1000) {
+    float percentage = 0.0f;
+    if (request->contentLength() != 0) {
+      // Note: Using contentLength() for progress calculation is technically wrong as it includes
+      // multipart headers/boundaries, but it's only off by a small amount and we don't have
+      // access to the actual firmware size until the upload is complete. This is intentional
+      // as it still gives the user a reasonable progress indication.
+      percentage = (this->ota_read_length_ * 100.0f) / request->contentLength();
+      ESP_LOGD(TAG, "OTA in progress: %0.1f%%", percentage);
+    } else {
+      ESP_LOGD(TAG, "OTA in progress: %u bytes read", this->ota_read_length_);
+    }
+#ifdef USE_OTA_STATE_CALLBACK
+    // Report progress - use call_deferred since we're in web server task
+    this->parent_->state_callback_.call_deferred(ota::OTA_IN_PROGRESS, percentage, 0);
+#endif
+    this->last_ota_progress_ = now;
+  }
+}
+
+void OTARequestHandler::schedule_ota_reboot_() {
+  ESP_LOGI(TAG, "OTA update successful!");
+  this->parent_->set_timeout(100, []() {
+    ESP_LOGI(TAG, "Performing OTA reboot now");
+    App.safe_reboot();
+  });
+}
+
+void OTARequestHandler::ota_init_(const char *filename) {
+  ESP_LOGI(TAG, "OTA Update Start: %s", filename);
+  this->ota_read_length_ = 0;
+  this->ota_success_ = false;
+}
+
+void OTARequestHandler::handleUpload(AsyncWebServerRequest *request, const String &filename, size_t index,
+                                     uint8_t *data, size_t len, bool final) {
+  ota::OTAResponseTypes error_code = ota::OTA_RESPONSE_OK;
+
+  if (index == 0 && !this->ota_backend_) {
+    // Initialize OTA on first call
+    this->ota_init_(filename.c_str());
+
+#ifdef USE_OTA_STATE_CALLBACK
+    // Notify OTA started - use call_deferred since we're in web server task
+    this->parent_->state_callback_.call_deferred(ota::OTA_STARTED, 0.0f, 0);
+#endif
+
+    // Platform-specific pre-initialization
+#ifdef USE_ARDUINO
+#ifdef USE_ESP8266
+    Update.runAsync(true);
+#endif
+#if defined(USE_ESP32) || defined(USE_LIBRETINY)
+    if (Update.isRunning()) {
+      Update.abort();
+    }
+#endif
+#endif  // USE_ARDUINO
+
+    this->ota_backend_ = ota::make_ota_backend();
+    if (!this->ota_backend_) {
+      ESP_LOGE(TAG, "Failed to create OTA backend");
+#ifdef USE_OTA_STATE_CALLBACK
+      this->parent_->state_callback_.call_deferred(ota::OTA_ERROR, 0.0f,
+                                                   static_cast<uint8_t>(ota::OTA_RESPONSE_ERROR_UNKNOWN));
+#endif
+      return;
+    }
+
+    // Web server OTA uses multipart uploads where the actual firmware size
+    // is unknown (contentLength includes multipart overhead)
+    // Pass 0 to indicate unknown size
+    error_code = this->ota_backend_->begin(0);
+    if (error_code != ota::OTA_RESPONSE_OK) {
+      ESP_LOGE(TAG, "OTA begin failed: %d", error_code);
+      this->ota_backend_.reset();
+#ifdef USE_OTA_STATE_CALLBACK
+      this->parent_->state_callback_.call_deferred(ota::OTA_ERROR, 0.0f, static_cast<uint8_t>(error_code));
+#endif
+      return;
+    }
+  }
+
+  if (!this->ota_backend_) {
+    return;
+  }
+
+  // Process data
+  if (len > 0) {
+    error_code = this->ota_backend_->write(data, len);
+    if (error_code != ota::OTA_RESPONSE_OK) {
+      ESP_LOGE(TAG, "OTA write failed: %d", error_code);
+      this->ota_backend_->abort();
+      this->ota_backend_.reset();
+#ifdef USE_OTA_STATE_CALLBACK
+      this->parent_->state_callback_.call_deferred(ota::OTA_ERROR, 0.0f, static_cast<uint8_t>(error_code));
+#endif
+      return;
+    }
+    this->ota_read_length_ += len;
+    this->report_ota_progress_(request);
+  }
+
+  // Finalize
+  if (final) {
+    ESP_LOGD(TAG, "OTA final chunk: index=%u, len=%u, total_read=%u, contentLength=%u", index, len,
+             this->ota_read_length_, request->contentLength());
+
+    // For Arduino framework, the Update library tracks expected size from firmware header
+    // If we haven't received enough data, calling end() will fail
+    // This can happen if the upload is interrupted or the client disconnects
+    error_code = this->ota_backend_->end();
+    if (error_code == ota::OTA_RESPONSE_OK) {
+      this->ota_success_ = true;
+#ifdef USE_OTA_STATE_CALLBACK
+      // Report completion before reboot - use call_deferred since we're in web server task
+      this->parent_->state_callback_.call_deferred(ota::OTA_COMPLETED, 100.0f, 0);
+#endif
+      this->schedule_ota_reboot_();
+    } else {
+      ESP_LOGE(TAG, "OTA end failed: %d", error_code);
+#ifdef USE_OTA_STATE_CALLBACK
+      this->parent_->state_callback_.call_deferred(ota::OTA_ERROR, 0.0f, static_cast<uint8_t>(error_code));
+#endif
+    }
+    this->ota_backend_.reset();
+  }
+}
+
+void OTARequestHandler::handleRequest(AsyncWebServerRequest *request) {
+  AsyncWebServerResponse *response;
+  // Use the ota_success_ flag to determine the actual result
+  const char *msg = this->ota_success_ ? "Update Successful!" : "Update Failed!";
+  response = request->beginResponse(200, "text/plain", msg);
+  response->addHeader("Connection", "close");
+  request->send(response);
+}
+
+void WebServerOTAComponent::setup() {
+  // Get the global web server base instance and register our handler
+  auto *base = web_server_base::global_web_server_base;
+  if (base == nullptr) {
+    ESP_LOGE(TAG, "WebServerBase not found");
+    this->mark_failed();
+    return;
+  }
+
+  // AsyncWebServer takes ownership of the handler and will delete it when the server is destroyed
+  base->add_handler(new OTARequestHandler(this));  // NOLINT
+#ifdef USE_OTA_STATE_CALLBACK
+  // Register with global OTA callback system
+  ota::register_ota_platform(this);
+#endif
+}
+
+void WebServerOTAComponent::dump_config() { ESP_LOGCONFIG(TAG, "Web Server OTA"); }
+
+}  // namespace web_server
+}  // namespace esphome
+
+#endif  // USE_WEBSERVER_OTA

esphome/components/web_server/ota/ota_web_server.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "esphome/core/defines.h"
+#ifdef USE_WEBSERVER_OTA
+
+#include "esphome/components/ota/ota_backend.h"
+#include "esphome/components/web_server_base/web_server_base.h"
+#include "esphome/core/component.h"
+
+namespace esphome {
+namespace web_server {
+
+class WebServerOTAComponent : public ota::OTAComponent {
+ public:
+  void setup() override;
+  void dump_config() override;
+  float get_setup_priority() const override { return setup_priority::AFTER_WIFI; }
+
+ protected:
+  friend class OTARequestHandler;
+};
+
+}  // namespace web_server
+}  // namespace esphome
+
+#endif  // USE_WEBSERVER_OTA

esphome/components/web_server/web_server.cpp

@@ -273,7 +273,11 @@ std::string WebServer::get_config_json() {
   return json::build_json([this](JsonObject root) {
     root["title"] = App.get_friendly_name().empty() ? App.get_name() : App.get_friendly_name();
     root["comment"] = App.get_comment();
-    root["ota"] = this->allow_ota_;
+#ifdef USE_WEBSERVER_OTA
+    root["ota"] = true;  // web_server OTA platform is configured
+#else
+    root["ota"] = false;
+#endif
     root["log"] = this->expose_log_;
     root["lang"] = "en";
   });
@@ -299,10 +303,7 @@ void WebServer::setup() {
 #endif
   this->base_->add_handler(this);
 
-#ifdef USE_WEBSERVER_OTA
-  if (this->allow_ota_)
-    this->base_->add_ota_handler();
-#endif
+  // OTA is now handled by the web_server OTA platform
 
   // doesn't need defer functionality - if the queue is full, the client JS knows it's alive because it's clearly
   // getting a lot of events

esphome/components/web_server/web_server.h

@@ -212,11 +212,6 @@ class WebServer : public Controller, public Component, public AsyncWebHandler {
    * @param include_internal Whether internal components should be displayed.
    */
   void set_include_internal(bool include_internal) { include_internal_ = include_internal; }
-  /** Set whether or not the webserver should expose the OTA form and handler.
-   *
-   * @param allow_ota.
-   */
-  void set_allow_ota(bool allow_ota) { this->allow_ota_ = allow_ota; }
   /** Set whether or not the webserver should expose the Log.
    *
    * @param expose_log.
@@ -525,7 +520,6 @@ class WebServer : public Controller, public Component, public AsyncWebHandler {
 #ifdef USE_WEBSERVER_JS_INCLUDE
   const char *js_include_{nullptr};
 #endif
-  bool allow_ota_{true};
   bool expose_log_{true};
 #ifdef USE_ESP32
   std::deque<std::function<void()>> to_schedule_;

esphome/components/web_server/web_server_v1.cpp

@@ -192,11 +192,10 @@ void WebServer::handle_index_request(AsyncWebServerRequest *request) {
 
   stream->print(F("</tbody></table><p>See <a href=\"https://esphome.io/web-api/index.html\">ESPHome Web API</a> for "
                   "REST API documentation.</p>"));
-  if (this->allow_ota_) {
-    stream->print(
-        F("<h2>OTA Update</h2><form method=\"POST\" action=\"/update\" enctype=\"multipart/form-data\"><input "
-          "type=\"file\" name=\"update\"><input type=\"submit\" value=\"Update\"></form>"));
-  }
+#ifdef USE_WEBSERVER_OTA
+  stream->print(F("<h2>OTA Update</h2><form method=\"POST\" action=\"/update\" enctype=\"multipart/form-data\"><input "
+                  "type=\"file\" name=\"update\"><input type=\"submit\" value=\"Update\"></form>"));
+#endif
   stream->print(F("<h2>Debug Log</h2><pre id=\"log\"></pre>"));
 #ifdef USE_WEBSERVER_JS_INCLUDE
   if (this->js_include_ != nullptr) {

esphome/components/web_server_base/__init__.py

@@ -30,6 +30,7 @@ CONFIG_SCHEMA = cv.Schema(
 async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
+    cg.add(cg.RawExpression(f"{web_server_base_ns}::global_web_server_base = {var}"))
 
     if CORE.using_arduino:
         if CORE.is_esp32:

esphome/components/web_server_base/web_server_base.cpp

@@ -4,123 +4,12 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-#ifdef USE_ARDUINO
-#include <StreamString.h>
-#if defined(USE_ESP32) || defined(USE_LIBRETINY)
-#include <Update.h>
-#endif
-#ifdef USE_ESP8266
-#include <Updater.h>
-#endif
-#endif
-
-#if defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)
-#include <esp_ota_ops.h>
-#include <esp_task_wdt.h>
-#endif
-
 namespace esphome {
 namespace web_server_base {
 
 static const char *const TAG = "web_server_base";
 
-#if defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)
-// Minimal OTA backend implementation for web server
-// This allows OTA updates via web server without requiring the OTA component
-// TODO: In the future, this should be refactored into a common ota_base component
-// that both web_server and ota components can depend on, avoiding code duplication
-// while keeping the components independent. This would allow both ESP-IDF and Arduino
-// implementations to share the base OTA functionality without requiring the full OTA component.
-// The IDFWebServerOTABackend class is intentionally designed with the same interface
-// as OTABackend to make it easy to swap to using OTABackend when the ota component
-// is split into ota and ota_base in the future.
-class IDFWebServerOTABackend {
- public:
-  bool begin() {
-    this->partition_ = esp_ota_get_next_update_partition(nullptr);
-    if (this->partition_ == nullptr) {
-      ESP_LOGE(TAG, "No OTA partition available");
-      return false;
-    }
-
-#if CONFIG_ESP_TASK_WDT_TIMEOUT_S < 15
-    // The following function takes longer than the default timeout of WDT due to flash erase
-#if ESP_IDF_VERSION_MAJOR >= 5
-    esp_task_wdt_config_t wdtc;
-    wdtc.idle_core_mask = 0;
-#if CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU0
-    wdtc.idle_core_mask |= (1 << 0);
-#endif
-#if CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU1
-    wdtc.idle_core_mask |= (1 << 1);
-#endif
-    wdtc.timeout_ms = 15000;
-    wdtc.trigger_panic = false;
-    esp_task_wdt_reconfigure(&wdtc);
-#else
-    esp_task_wdt_init(15, false);
-#endif
-#endif
-
-    esp_err_t err = esp_ota_begin(this->partition_, 0, &this->update_handle_);
-
-#if CONFIG_ESP_TASK_WDT_TIMEOUT_S < 15
-    // Set the WDT back to the configured timeout
-#if ESP_IDF_VERSION_MAJOR >= 5
-    wdtc.timeout_ms = CONFIG_ESP_TASK_WDT_TIMEOUT_S * 1000;
-    esp_task_wdt_reconfigure(&wdtc);
-#else
-    esp_task_wdt_init(CONFIG_ESP_TASK_WDT_TIMEOUT_S, false);
-#endif
-#endif
-
-    if (err != ESP_OK) {
-      esp_ota_abort(this->update_handle_);
-      this->update_handle_ = 0;
-      ESP_LOGE(TAG, "esp_ota_begin failed: %s", esp_err_to_name(err));
-      return false;
-    }
-    return true;
-  }
-
-  bool write(uint8_t *data, size_t len) {
-    esp_err_t err = esp_ota_write(this->update_handle_, data, len);
-    if (err != ESP_OK) {
-      ESP_LOGE(TAG, "esp_ota_write failed: %s", esp_err_to_name(err));
-      return false;
-    }
-    return true;
-  }
-
-  bool end() {
-    esp_err_t err = esp_ota_end(this->update_handle_);
-    this->update_handle_ = 0;
-    if (err != ESP_OK) {
-      ESP_LOGE(TAG, "esp_ota_end failed: %s", esp_err_to_name(err));
-      return false;
-    }
-
-    err = esp_ota_set_boot_partition(this->partition_);
-    if (err != ESP_OK) {
-      ESP_LOGE(TAG, "esp_ota_set_boot_partition failed: %s", esp_err_to_name(err));
-      return false;
-    }
-
-    return true;
-  }
-
-  void abort() {
-    if (this->update_handle_ != 0) {
-      esp_ota_abort(this->update_handle_);
-      this->update_handle_ = 0;
-    }
-  }
-
- private:
-  esp_ota_handle_t update_handle_{0};
-  const esp_partition_t *partition_{nullptr};
-};
-#endif
+WebServerBase *global_web_server_base = nullptr;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
 void WebServerBase::add_handler(AsyncWebHandler *handler) {
   // remove all handlers
@@ -134,157 +23,6 @@ void WebServerBase::add_handler(AsyncWebHandler *handler) {
   }
 }
 
-#ifdef USE_WEBSERVER_OTA
-void OTARequestHandler::report_ota_progress_(AsyncWebServerRequest *request) {
-  const uint32_t now = millis();
-  if (now - this->last_ota_progress_ > 1000) {
-    if (request->contentLength() != 0) {
-      float percentage = (this->ota_read_length_ * 100.0f) / request->contentLength();
-      ESP_LOGD(TAG, "OTA in progress: %0.1f%%", percentage);
-    } else {
-      ESP_LOGD(TAG, "OTA in progress: %u bytes read", this->ota_read_length_);
-    }
-    this->last_ota_progress_ = now;
-  }
-}
-
-void OTARequestHandler::schedule_ota_reboot_() {
-  ESP_LOGI(TAG, "OTA update successful!");
-  this->parent_->set_timeout(100, []() {
-    ESP_LOGI(TAG, "Performing OTA reboot now");
-    App.safe_reboot();
-  });
-}
-
-void OTARequestHandler::ota_init_(const char *filename) {
-  ESP_LOGI(TAG, "OTA Update Start: %s", filename);
-  this->ota_read_length_ = 0;
-}
-
-void report_ota_error() {
-#ifdef USE_ARDUINO
-  StreamString ss;
-  Update.printError(ss);
-  ESP_LOGW(TAG, "OTA Update failed! Error: %s", ss.c_str());
-#endif
-}
-
-void OTARequestHandler::handleUpload(AsyncWebServerRequest *request, const String &filename, size_t index,
-                                     uint8_t *data, size_t len, bool final) {
-#ifdef USE_ARDUINO
-  bool success;
-  if (index == 0) {
-    this->ota_init_(filename.c_str());
-#ifdef USE_ESP8266
-    Update.runAsync(true);
-    // NOLINTNEXTLINE(readability-static-accessed-through-instance)
-    success = Update.begin((ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000);
-#endif
-#if defined(USE_ESP32_FRAMEWORK_ARDUINO) || defined(USE_LIBRETINY)
-    if (Update.isRunning()) {
-      Update.abort();
-    }
-    success = Update.begin(UPDATE_SIZE_UNKNOWN, U_FLASH);
-#endif
-    if (!success) {
-      report_ota_error();
-      return;
-    }
-  } else if (Update.hasError()) {
-    // don't spam logs with errors if something failed at start
-    return;
-  }
-
-  success = Update.write(data, len) == len;
-  if (!success) {
-    report_ota_error();
-    return;
-  }
-  this->ota_read_length_ += len;
-  this->report_ota_progress_(request);
-
-  if (final) {
-    if (Update.end(true)) {
-      this->schedule_ota_reboot_();
-    } else {
-      report_ota_error();
-    }
-  }
-#endif  // USE_ARDUINO
-
-#ifdef USE_ESP_IDF
-  // ESP-IDF implementation
-  if (index == 0 && !this->ota_backend_) {
-    // Initialize OTA on first call
-    this->ota_init_(filename.c_str());
-    this->ota_success_ = false;
-
-    auto *backend = new IDFWebServerOTABackend();
-    if (!backend->begin()) {
-      ESP_LOGE(TAG, "OTA begin failed");
-      delete backend;
-      return;
-    }
-    this->ota_backend_ = backend;
-  }
-
-  auto *backend = static_cast<IDFWebServerOTABackend *>(this->ota_backend_);
-  if (!backend) {
-    return;
-  }
-
-  // Process data
-  if (len > 0) {
-    if (!backend->write(data, len)) {
-      ESP_LOGE(TAG, "OTA write failed");
-      backend->abort();
-      delete backend;
-      this->ota_backend_ = nullptr;
-      return;
-    }
-    this->ota_read_length_ += len;
-    this->report_ota_progress_(request);
-  }
-
-  // Finalize
-  if (final) {
-    this->ota_success_ = backend->end();
-    if (this->ota_success_) {
-      this->schedule_ota_reboot_();
-    } else {
-      ESP_LOGE(TAG, "OTA end failed");
-    }
-    delete backend;
-    this->ota_backend_ = nullptr;
-  }
-#endif  // USE_ESP_IDF
-}
-
-void OTARequestHandler::handleRequest(AsyncWebServerRequest *request) {
-  AsyncWebServerResponse *response;
-#ifdef USE_ARDUINO
-  if (!Update.hasError()) {
-    response = request->beginResponse(200, "text/plain", "Update Successful!");
-  } else {
-    StreamString ss;
-    ss.print("Update Failed: ");
-    Update.printError(ss);
-    response = request->beginResponse(200, "text/plain", ss);
-  }
-#endif  // USE_ARDUINO
-#ifdef USE_ESP_IDF
-  // Send response based on the OTA result
-  response = request->beginResponse(200, "text/plain", this->ota_success_ ? "Update Successful!" : "Update Failed!");
-#endif  // USE_ESP_IDF
-  response->addHeader("Connection", "close");
-  request->send(response);
-}
-
-void WebServerBase::add_ota_handler() {
-  this->add_handler(new OTARequestHandler(this));  // NOLINT
-}
-#endif
-
 float WebServerBase::get_setup_priority() const {
   // Before WiFi (captive portal)
   return setup_priority::WIFI + 2.0f;

esphome/components/web_server_base/web_server_base.h

@@ -17,6 +17,9 @@
 namespace esphome {
 namespace web_server_base {
 
+class WebServerBase;
+extern WebServerBase *global_web_server_base;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
 namespace internal {
 
 class MiddlewareHandler : public AsyncWebHandler {
@@ -110,18 +113,10 @@ class WebServerBase : public Component {
 
   void add_handler(AsyncWebHandler *handler);
 
-#ifdef USE_WEBSERVER_OTA
-  void add_ota_handler();
-#endif
-
   void set_port(uint16_t port) { port_ = port; }
   uint16_t get_port() const { return port_; }
 
  protected:
-#ifdef USE_WEBSERVER_OTA
-  friend class OTARequestHandler;
-#endif
-
   int initialized_{0};
   uint16_t port_{80};
   std::shared_ptr<AsyncWebServer> server_{nullptr};
@@ -129,37 +124,6 @@ class WebServerBase : public Component {
   internal::Credentials credentials_;
 };
 
-#ifdef USE_WEBSERVER_OTA
-class OTARequestHandler : public AsyncWebHandler {
- public:
-  OTARequestHandler(WebServerBase *parent) : parent_(parent) {}
-  void handleRequest(AsyncWebServerRequest *request) override;
-  void handleUpload(AsyncWebServerRequest *request, const String &filename, size_t index, uint8_t *data, size_t len,
-                    bool final) override;
-  bool canHandle(AsyncWebServerRequest *request) const override {
-    return request->url() == "/update" && request->method() == HTTP_POST;
-  }
-
-  // NOLINTNEXTLINE(readability-identifier-naming)
-  bool isRequestHandlerTrivial() const override { return false; }
-
- protected:
-  void report_ota_progress_(AsyncWebServerRequest *request);
-  void schedule_ota_reboot_();
-  void ota_init_(const char *filename);
-
-  uint32_t last_ota_progress_{0};
-  uint32_t ota_read_length_{0};
-  WebServerBase *parent_;
-
- private:
-#ifdef USE_ESP_IDF
-  void *ota_backend_{nullptr};
-  bool ota_success_{false};
-#endif
-};
-#endif  // USE_WEBSERVER_OTA
-
 }  // namespace web_server_base
 }  // namespace esphome
 #endif

esphome/components/web_server_idf/__init__.py

@@ -1,7 +1,5 @@
-from esphome.components.esp32 import add_idf_component, add_idf_sdkconfig_option
+from esphome.components.esp32 import add_idf_sdkconfig_option
 import esphome.config_validation as cv
-from esphome.const import CONF_OTA, CONF_WEB_SERVER
-from esphome.core import CORE
 
 CODEOWNERS = ["@dentra"]
 
@@ -14,7 +12,3 @@ CONFIG_SCHEMA = cv.All(
 async def to_code(config):
     # Increase the maximum supported size of headers section in HTTP request packet to be processed by the server
     add_idf_sdkconfig_option("CONFIG_HTTPD_MAX_REQ_HDR_LEN", 1024)
-    # Check if web_server component has OTA enabled
-    if CORE.config.get(CONF_WEB_SERVER, {}).get(CONF_OTA, True):
-        # Add multipart parser component for ESP-IDF OTA support
-        add_idf_component(name="zorxx/multipart-parser", ref="1.0.1")

esphome/config.py

@@ -67,6 +67,42 @@ ConfigPath = list[str | int]
 path_context = contextvars.ContextVar("Config path")
 
 
+def _process_platform_config(
+    result: Config,
+    component_name: str,
+    platform_name: str,
+    platform_config: ConfigType,
+    path: ConfigPath,
+) -> None:
+    """Process a platform configuration and add necessary validation steps.
+
+    This is shared between LoadValidationStep and AutoLoadValidationStep to avoid duplication.
+    """
+    # Get the platform manifest
+    platform = get_platform(component_name, platform_name)
+    if platform is None:
+        result.add_str_error(
+            f"Platform not found: '{component_name}.{platform_name}'", path
+        )
+        return
+
+    # Add platform to loaded integrations
+    CORE.loaded_integrations.add(platform_name)
+    CORE.loaded_platforms.add(f"{component_name}/{platform_name}")
+
+    # Process platform's AUTO_LOAD
+    for load in platform.auto_load:
+        if load not in result:
+            result.add_validation_step(AutoLoadValidationStep(load))
+
+    # Add validation steps for the platform
+    p_domain = f"{component_name}.{platform_name}"
+    result.add_output_path(path, p_domain)
+    result.add_validation_step(
+        MetadataValidationStep(path, p_domain, platform_config, platform)
+    )
+
+
 def _path_begins_with(path: ConfigPath, other: ConfigPath) -> bool:
     if len(path) < len(other):
         return False
@@ -379,26 +415,11 @@ class LoadValidationStep(ConfigValidationStep):
                     path,
                 )
                 continue
-            # Remove temp output path and construct new one
+            # Remove temp output path
             result.remove_output_path(path, p_domain)
-            p_domain = f"{self.domain}.{p_name}"
-            result.add_output_path(path, p_domain)
-            # Try Load platform
-            platform = get_platform(self.domain, p_name)
-            if platform is None:
-                result.add_str_error(f"Platform not found: '{p_domain}'", path)
-                continue
-            CORE.loaded_integrations.add(p_name)
-            CORE.loaded_platforms.add(f"{self.domain}/{p_name}")
 
-            # Process AUTO_LOAD
-            for load in platform.auto_load:
-                if load not in result:
-                    result.add_validation_step(AutoLoadValidationStep(load))
-
-            result.add_validation_step(
-                MetadataValidationStep(path, p_domain, p_config, platform)
-            )
+            # Process the platform configuration
+            _process_platform_config(result, self.domain, p_name, p_config, path)
 
 
 class AutoLoadValidationStep(ConfigValidationStep):
@@ -413,10 +434,56 @@ class AutoLoadValidationStep(ConfigValidationStep):
         self.domain = domain
 
     def run(self, result: Config) -> None:
-        if self.domain in result:
-            # already loaded
+        # Regular component auto-load (no platform)
+        if "." not in self.domain:
+            if self.domain in result:
+                # already loaded
+                return
+            result.add_validation_step(LoadValidationStep(self.domain, core.AutoLoad()))
             return
-        result.add_validation_step(LoadValidationStep(self.domain, core.AutoLoad()))
+
+        # Platform-specific auto-load (e.g., "ota.web_server")
+        component_name, _, platform_name = self.domain.partition(".")
+
+        # Check if component exists
+        if component_name not in result:
+            # Component doesn't exist, load it first
+            result.add_validation_step(LoadValidationStep(component_name, []))
+            # Re-run this step after the component is loaded
+            result.add_validation_step(AutoLoadValidationStep(self.domain))
+            return
+
+        # Component exists, check if it's a platform component
+        component = get_component(component_name)
+        if component is None or not component.is_platform_component:
+            result.add_str_error(
+                f"Component {component_name} is not a platform component, "
+                f"cannot auto-load platform {platform_name}",
+                [component_name],
+            )
+            return
+
+        # Ensure the component config is a list
+        component_conf = result.get(component_name)
+        if not isinstance(component_conf, list):
+            component_conf = result[component_name] = []
+
+        # Check if platform already exists
+        if any(
+            isinstance(conf, dict) and conf.get(CONF_PLATFORM) == platform_name
+            for conf in component_conf
+        ):
+            return
+
+        # Add and process the platform configuration
+        platform_conf = core.AutoLoad()
+        platform_conf[CONF_PLATFORM] = platform_name
+        component_conf.append(platform_conf)
+
+        path = [component_name, len(component_conf) - 1]
+        _process_platform_config(
+            result, component_name, platform_name, platform_conf, path
+        )
 
 
 class MetadataValidationStep(ConfigValidationStep):

esphome/core/application.cpp

@@ -84,6 +84,10 @@ void Application::setup() {
   }
 
   ESP_LOGI(TAG, "setup() finished successfully!");
+
+  // Clear setup priority overrides to free memory
+  clear_setup_priority_overrides();
+
   this->schedule_dump_config();
   this->calculate_looping_components_();
 }

esphome/core/component.cpp

@@ -2,7 +2,9 @@
 
 #include <cinttypes>
 #include <limits>
+#include <memory>
 #include <utility>
+#include <vector>
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
@@ -12,6 +14,30 @@ namespace esphome {
 
 static const char *const TAG = "component";
 
+// Global vectors for component data that doesn't belong in every instance.
+// Using vector instead of unordered_map for both because:
+// - Much lower memory overhead (8 bytes per entry vs 20+ for unordered_map)
+// - Linear search is fine for small n (typically < 5 entries)
+// - These are rarely accessed (setup only or error cases only)
+
+// Component error messages - only stores messages for failed components
+// Lazy allocated since most configs have zero failures
+// Note: We don't clear this vector because:
+// 1. Components are never destroyed in ESPHome
+// 2. Failed components remain failed (no recovery mechanism)
+// 3. Memory usage is minimal (only failures with custom messages are stored)
+static std::unique_ptr<std::vector<std::pair<const Component *, const char *>>> &get_component_error_messages() {
+  static std::unique_ptr<std::vector<std::pair<const Component *, const char *>>> instance;
+  return instance;
+}
+
+// Setup priority overrides - freed after setup completes
+// Typically < 5 entries, lazy allocated
+static std::unique_ptr<std::vector<std::pair<const Component *, float>>> &get_setup_priority_overrides() {
+  static std::unique_ptr<std::vector<std::pair<const Component *, float>>> instance;
+  return instance;
+}
+
 namespace setup_priority {
 
 const float BUS = 1000.0f;
@@ -102,8 +128,17 @@ void Component::call_setup() { this->setup(); }
 void Component::call_dump_config() {
   this->dump_config();
   if (this->is_failed()) {
-    ESP_LOGE(TAG, "  Component %s is marked FAILED: %s", this->get_component_source(),
-             this->error_message_ ? this->error_message_ : "unspecified");
+    // Look up error message from global vector
+    const char *error_msg = "unspecified";
+    if (get_component_error_messages()) {
+      for (const auto &pair : *get_component_error_messages()) {
+        if (pair.first == this) {
+          error_msg = pair.second;
+          break;
+        }
+      }
+    }
+    ESP_LOGE(TAG, "  Component %s is marked FAILED: %s", this->get_component_source(), error_msg);
   }
 }
 
@@ -245,8 +280,21 @@ void Component::status_set_error(const char *message) {
   this->component_state_ |= STATUS_LED_ERROR;
   App.app_state_ |= STATUS_LED_ERROR;
   ESP_LOGE(TAG, "Component %s set Error flag: %s", this->get_component_source(), message);
-  if (strcmp(message, "unspecified") != 0)
-    this->error_message_ = message;
+  if (strcmp(message, "unspecified") != 0) {
+    // Lazy allocate the error messages vector if needed
+    if (!get_component_error_messages()) {
+      get_component_error_messages() = std::make_unique<std::vector<std::pair<const Component *, const char *>>>();
+    }
+    // Check if this component already has an error message
+    for (auto &pair : *get_component_error_messages()) {
+      if (pair.first == this) {
+        pair.second = message;
+        return;
+      }
+    }
+    // Add new error message
+    get_component_error_messages()->emplace_back(this, message);
+  }
 }
 void Component::status_clear_warning() {
   if ((this->component_state_ & STATUS_LED_WARNING) == 0)
@@ -270,11 +318,36 @@ void Component::status_momentary_error(const std::string &name, uint32_t length)
 }
 void Component::dump_config() {}
 float Component::get_actual_setup_priority() const {
-  if (std::isnan(this->setup_priority_override_))
-    return this->get_setup_priority();
-  return this->setup_priority_override_;
+  // Check if there's an override in the global vector
+  if (get_setup_priority_overrides()) {
+    // Linear search is fine for small n (typically < 5 overrides)
+    for (const auto &pair : *get_setup_priority_overrides()) {
+      if (pair.first == this) {
+        return pair.second;
+      }
+    }
+  }
+  return this->get_setup_priority();
+}
+void Component::set_setup_priority(float priority) {
+  // Lazy allocate the vector if needed
+  if (!get_setup_priority_overrides()) {
+    get_setup_priority_overrides() = std::make_unique<std::vector<std::pair<const Component *, float>>>();
+    // Reserve some space to avoid reallocations (most configs have < 10 overrides)
+    get_setup_priority_overrides()->reserve(10);
+  }
+
+  // Check if this component already has an override
+  for (auto &pair : *get_setup_priority_overrides()) {
+    if (pair.first == this) {
+      pair.second = priority;
+      return;
+    }
+  }
+
+  // Add new override
+  get_setup_priority_overrides()->emplace_back(this, priority);
 }
-void Component::set_setup_priority(float priority) { this->setup_priority_override_ = priority; }
 
 bool Component::has_overridden_loop() const {
 #if defined(USE_HOST) || defined(CLANG_TIDY)
@@ -336,4 +409,9 @@ uint32_t WarnIfComponentBlockingGuard::finish() {
 
 WarnIfComponentBlockingGuard::~WarnIfComponentBlockingGuard() {}
 
+void clear_setup_priority_overrides() {
+  // Free the setup priority map completely
+  get_setup_priority_overrides().reset();
+}
+
 }  // namespace esphome

esphome/core/component.h

@@ -387,9 +387,7 @@ class Component {
   bool cancel_defer(const std::string &name);  // NOLINT
 
   // Ordered for optimal packing on 32-bit systems
-  float setup_priority_override_{NAN};
   const char *component_source_{nullptr};
-  const char *error_message_{nullptr};
   uint16_t warn_if_blocking_over_{WARN_IF_BLOCKING_OVER_MS};  ///< Warn if blocked for this many ms (max 65.5s)
   /// State of this component - each bit has a purpose:
   /// Bits 0-1: Component state (0x00=CONSTRUCTION, 0x01=SETUP, 0x02=LOOP, 0x03=FAILED)
@@ -459,4 +457,7 @@ class WarnIfComponentBlockingGuard {
   Component *component_;
 };
 
+// Function to clear setup priority overrides after all components are set up
+void clear_setup_priority_overrides();
+
 }  // namespace esphome

esphome/core/helpers.cpp

@@ -4,13 +4,13 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
 
+#include <strings.h>
 #include <algorithm>
 #include <cctype>
 #include <cmath>
 #include <cstdarg>
 #include <cstdio>
 #include <cstring>
-#include <strings.h>
 
 #ifdef USE_HOST
 #ifndef _WIN32
@@ -43,10 +43,10 @@
 #include <random>
 #endif
 #ifdef USE_ESP32
-#include "rom/crc.h"
-#include "esp_mac.h"
 #include "esp_efuse.h"
 #include "esp_efuse_table.h"
+#include "esp_mac.h"
+#include "rom/crc.h"
 #endif
 
 #ifdef USE_LIBRETINY
@@ -393,6 +393,21 @@ std::string format_hex_pretty(const uint16_t *data, size_t length) {
   return ret;
 }
 std::string format_hex_pretty(const std::vector<uint16_t> &data) { return format_hex_pretty(data.data(), data.size()); }
+std::string format_hex_pretty(const std::string &data) {
+  if (data.empty())
+    return "";
+  std::string ret;
+  ret.resize(3 * data.length() - 1);
+  for (size_t i = 0; i < data.length(); i++) {
+    ret[3 * i] = format_hex_pretty_char((data[i] & 0xF0) >> 4);
+    ret[3 * i + 1] = format_hex_pretty_char(data[i] & 0x0F);
+    if (i != data.length() - 1)
+      ret[3 * i + 2] = '.';
+  }
+  if (data.length() > 4)
+    return ret + " (" + std::to_string(data.length()) + ")";
+  return ret;
+}
 
 std::string format_bin(const uint8_t *data, size_t length) {
   std::string result;

esphome/core/helpers.h

@@ -348,6 +348,8 @@ std::string format_hex_pretty(const uint16_t *data, size_t length);
 std::string format_hex_pretty(const std::vector<uint8_t> &data);
 /// Format the vector \p data in pretty-printed, human-readable hex.
 std::string format_hex_pretty(const std::vector<uint16_t> &data);
+/// Format the string \p data in pretty-printed, human-readable hex.
+std::string format_hex_pretty(const std::string &data);
 /// Format an unsigned integer in pretty-printed, human-readable hex, starting with the most significant byte.
 template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0> std::string format_hex_pretty(T val) {
   val = convert_big_endian(val);

esphome/platformio_api.py

@@ -5,6 +5,7 @@ import os
 from pathlib import Path
 import re
 import subprocess
+from typing import Any
 
 from esphome.const import CONF_COMPILE_PROCESS_LIMIT, CONF_ESPHOME, KEY_CORE
 from esphome.core import CORE, EsphomeError
@@ -104,7 +105,16 @@ def run_compile(config, verbose):
     args = []
     if CONF_COMPILE_PROCESS_LIMIT in config[CONF_ESPHOME]:
         args += [f"-j{config[CONF_ESPHOME][CONF_COMPILE_PROCESS_LIMIT]}"]
-    return run_platformio_cli_run(config, verbose, *args)
+    result = run_platformio_cli_run(config, verbose, *args)
+
+    # Run memory analysis if enabled
+    if config.get(CONF_ESPHOME, {}).get("analyze_memory", False):
+        try:
+            analyze_memory_usage(config)
+        except Exception as e:
+            _LOGGER.warning("Failed to analyze memory usage: %s", e)
+
+    return result
 
 
 def _run_idedata(config):
@@ -331,3 +341,93 @@ class IDEData:
             return f"{self.cc_path[:-7]}addr2line.exe"
 
         return f"{self.cc_path[:-3]}addr2line"
+
+    @property
+    def objdump_path(self) -> str:
+        # replace gcc at end with objdump
+
+        # Windows
+        if self.cc_path.endswith(".exe"):
+            return f"{self.cc_path[:-7]}objdump.exe"
+
+        return f"{self.cc_path[:-3]}objdump"
+
+    @property
+    def readelf_path(self) -> str:
+        # replace gcc at end with readelf
+
+        # Windows
+        if self.cc_path.endswith(".exe"):
+            return f"{self.cc_path[:-7]}readelf.exe"
+
+        return f"{self.cc_path[:-3]}readelf"
+
+
+def analyze_memory_usage(config: dict[str, Any]) -> None:
+    """Analyze memory usage by component after compilation."""
+    # Lazy import to avoid overhead when not needed
+    from esphome.analyze_memory import MemoryAnalyzer
+
+    idedata = get_idedata(config)
+
+    # Get paths to tools
+    elf_path = idedata.firmware_elf_path
+    objdump_path = idedata.objdump_path
+    readelf_path = idedata.readelf_path
+
+    # Debug logging
+    _LOGGER.debug("ELF path from idedata: %s", elf_path)
+
+    # Check if file exists
+    if not Path(elf_path).exists():
+        # Try alternate path
+        alt_path = Path(CORE.relative_build_path(".pioenvs", CORE.name, "firmware.elf"))
+        if alt_path.exists():
+            elf_path = str(alt_path)
+            _LOGGER.debug("Using alternate ELF path: %s", elf_path)
+        else:
+            _LOGGER.warning("ELF file not found at %s or %s", elf_path, alt_path)
+            return
+
+    # Extract external components from config
+    external_components = set()
+
+    # Get the list of built-in ESPHome components
+    from esphome.analyze_memory import get_esphome_components
+
+    builtin_components = get_esphome_components()
+
+    # Special non-component keys that appear in configs
+    NON_COMPONENT_KEYS = {
+        CONF_ESPHOME,
+        "substitutions",
+        "packages",
+        "globals",
+        "<<",
+    }
+
+    # Check all top-level keys in config
+    for key in config:
+        if key not in builtin_components and key not in NON_COMPONENT_KEYS:
+            # This is an external component
+            external_components.add(key)
+
+    _LOGGER.debug("Detected external components: %s", external_components)
+
+    # Create analyzer and run analysis
+    analyzer = MemoryAnalyzer(elf_path, objdump_path, readelf_path, external_components)
+    analyzer.analyze()
+
+    # Generate and print report
+    report = analyzer.generate_report()
+    _LOGGER.info("\n%s", report)
+
+    # Optionally save to file
+    if config.get(CONF_ESPHOME, {}).get("memory_report_file"):
+        report_file = Path(config[CONF_ESPHOME]["memory_report_file"])
+        if report_file.suffix == ".json":
+            report_file.write_text(analyzer.to_json())
+            _LOGGER.info("Memory report saved to %s", report_file)
+        else:
+            report_file.write_text(report)
+            _LOGGER.info("Memory report saved to %s", report_file)

script/api_protobuf/api_protobuf.py

@@ -530,7 +530,7 @@ class BytesType(TypeInfo):
     wire_type = WireType.LENGTH_DELIMITED  # Uses wire type 2
 
     def dump(self, name: str) -> str:
-        o = f'out.append("\'").append({name}).append("\'");'
+        o = f"out.append(format_hex_pretty({name}));"
         return o
 
     def get_size_calculation(self, name: str, force: bool = False) -> str:
@@ -1255,6 +1255,7 @@ def main() -> None:
     #include "api_pb2.h"
     #include "api_pb2_size.h"
     #include "esphome/core/log.h"
+    #include "esphome/core/helpers.h"
 
     #include <cinttypes>
 

tests/component_tests/ota/test_web_server_ota.py

@@ -0,0 +1,102 @@
+"""Tests for the web_server OTA platform."""
+
+from collections.abc import Callable
+
+
+def test_web_server_ota_generated(generate_main: Callable[[str], str]) -> None:
+    """Test that web_server OTA platform generates correct code."""
+    main_cpp = generate_main("tests/component_tests/ota/test_web_server_ota.yaml")
+
+    # Check that the web server OTA component is included
+    assert "WebServerOTAComponent" in main_cpp
+    assert "web_server::WebServerOTAComponent" in main_cpp
+
+    # Check that global web server base is referenced
+    assert "global_web_server_base" in main_cpp
+
+    # Check component is registered
+    assert "App.register_component(web_server_webserverotacomponent_id)" in main_cpp
+
+
+def test_web_server_ota_with_callbacks(generate_main: Callable[[str], str]) -> None:
+    """Test web_server OTA with state callbacks."""
+    main_cpp = generate_main(
+        "tests/component_tests/ota/test_web_server_ota_callbacks.yaml"
+    )
+
+    # Check that web server OTA component is present
+    assert "WebServerOTAComponent" in main_cpp
+
+    # Check that callbacks are configured
+    # The actual callback code is in the component implementation, not main.cpp
+    # But we can check that logger.log statements are present from the callbacks
+    assert "logger.log" in main_cpp
+    assert "OTA started" in main_cpp
+    assert "OTA completed" in main_cpp
+    assert "OTA error" in main_cpp
+
+
+def test_web_server_ota_idf_multipart(generate_main: Callable[[str], str]) -> None:
+    """Test that ESP-IDF builds include multipart parser dependency."""
+    main_cpp = generate_main("tests/component_tests/ota/test_web_server_ota_idf.yaml")
+
+    # Check that web server OTA component is present
+    assert "WebServerOTAComponent" in main_cpp
+
+    # For ESP-IDF builds, the framework type is esp-idf
+    # The multipart parser dependency is added by web_server_idf
+    assert "web_server::WebServerOTAComponent" in main_cpp
+
+
+def test_web_server_ota_without_web_server_fails(
+    generate_main: Callable[[str], str],
+) -> None:
+    """Test that web_server OTA requires web_server component."""
+    # This should fail during validation since web_server_base is required
+    # but we can't test validation failures with generate_main
+    # Instead, verify that both components are needed in valid config
+    main_cpp = generate_main("tests/component_tests/ota/test_web_server_ota.yaml")
+
+    # Both web server and OTA components should be present
+    assert "WebServer" in main_cpp
+    assert "WebServerOTAComponent" in main_cpp
+
+
+def test_multiple_ota_platforms(generate_main: Callable[[str], str]) -> None:
+    """Test multiple OTA platforms can coexist."""
+    main_cpp = generate_main("tests/component_tests/ota/test_web_server_ota_multi.yaml")
+
+    # Check all OTA platforms are included
+    assert "WebServerOTAComponent" in main_cpp
+    assert "ESPHomeOTAComponent" in main_cpp
+    assert "OtaHttpRequestComponent" in main_cpp
+
+    # Check components are from correct namespaces
+    assert "web_server::WebServerOTAComponent" in main_cpp
+    assert "esphome::ESPHomeOTAComponent" in main_cpp
+    assert "http_request::OtaHttpRequestComponent" in main_cpp
+
+
+def test_web_server_ota_arduino_with_auth(generate_main: Callable[[str], str]) -> None:
+    """Test web_server OTA with Arduino framework and authentication."""
+    main_cpp = generate_main(
+        "tests/component_tests/ota/test_web_server_ota_arduino.yaml"
+    )
+
+    # Check web server OTA component is present
+    assert "WebServerOTAComponent" in main_cpp
+
+    # Check authentication is set up for web server
+    assert "set_auth_username" in main_cpp
+    assert "set_auth_password" in main_cpp
+
+
+def test_web_server_ota_esp8266(generate_main: Callable[[str], str]) -> None:
+    """Test web_server OTA on ESP8266 platform."""
+    main_cpp = generate_main(
+        "tests/component_tests/ota/test_web_server_ota_esp8266.yaml"
+    )
+
+    # Check web server OTA component is present
+    assert "WebServerOTAComponent" in main_cpp
+    assert "web_server::WebServerOTAComponent" in main_cpp

tests/component_tests/ota/test_web_server_ota.yaml

@@ -0,0 +1,15 @@
+esphome:
+  name: test_web_server_ota
+
+esp32:
+  board: esp32dev
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+web_server:
+  port: 80
+
+ota:
+  - platform: web_server

tests/component_tests/ota/test_web_server_ota_arduino.yaml

@@ -0,0 +1,18 @@
+esphome:
+  name: test_web_server_ota_arduino
+
+esp32:
+  board: esp32dev
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+web_server:
+  port: 80
+  auth:
+    username: admin
+    password: admin
+
+ota:
+  - platform: web_server

tests/component_tests/ota/test_web_server_ota_callbacks.yaml

@@ -0,0 +1,31 @@
+esphome:
+  name: test_web_server_ota_callbacks
+
+esp32:
+  board: esp32dev
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+logger:
+
+web_server:
+  port: 80
+
+ota:
+  - platform: web_server
+    on_begin:
+      - logger.log: "OTA started"
+    on_progress:
+      - logger.log:
+          format: "OTA progress: %.1f%%"
+          args: ["x"]
+    on_end:
+      - logger.log: "OTA completed"
+    on_error:
+      - logger.log:
+          format: "OTA error: %d"
+          args: ["x"]
+    on_state_change:
+      - logger.log: "OTA state changed"

tests/component_tests/ota/test_web_server_ota_esp8266.yaml

@@ -0,0 +1,15 @@
+esphome:
+  name: test_web_server_ota_esp8266
+
+esp8266:
+  board: nodemcuv2
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+web_server:
+  port: 80
+
+ota:
+  - platform: web_server

tests/component_tests/ota/test_web_server_ota_idf.yaml

@@ -0,0 +1,17 @@
+esphome:
+  name: test_web_server_ota_idf
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+web_server:
+  port: 80
+
+ota:
+  - platform: web_server

tests/component_tests/ota/test_web_server_ota_multi.yaml

@@ -0,0 +1,21 @@
+esphome:
+  name: test_web_server_ota_multi
+
+esp32:
+  board: esp32dev
+
+wifi:
+  ssid: MySSID
+  password: password1
+
+web_server:
+  port: 80
+
+http_request:
+  verify_ssl: false
+
+ota:
+  - platform: esphome
+    password: "test_password"
+  - platform: web_server
+  - platform: http_request

tests/component_tests/web_server/test_ota_migration.py

@@ -0,0 +1,38 @@
+"""Tests for web_server OTA migration validation."""
+
+import pytest
+
+from esphome import config_validation as cv
+from esphome.types import ConfigType
+
+
+def test_web_server_ota_true_fails_validation() -> None:
+    """Test that web_server with ota: true fails validation with helpful message."""
+    from esphome.components.web_server import validate_ota_removed
+
+    # Config with ota: true should fail
+    config: ConfigType = {"ota": True}
+
+    with pytest.raises(cv.Invalid) as exc_info:
+        validate_ota_removed(config)
+
+    # Check error message contains migration instructions
+    error_msg = str(exc_info.value)
+    assert "has been removed from 'web_server'" in error_msg
+    assert "platform: web_server" in error_msg
+    assert "ota:" in error_msg
+
+
+def test_web_server_ota_false_passes_validation() -> None:
+    """Test that web_server with ota: false passes validation."""
+    from esphome.components.web_server import validate_ota_removed
+
+    # Config with ota: false should pass
+    config: ConfigType = {"ota": False}
+    result = validate_ota_removed(config)
+    assert result == config
+
+    # Config without ota should also pass
+    config: ConfigType = {}
+    result = validate_ota_removed(config)
+    assert result == config

tests/components/web_server/test_no_ota.esp32-idf.yaml

@@ -1,3 +1,11 @@
+esphome:
+  name: test-web-server-no-ota-idf
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
 packages:
   device_base: !include common.yaml
 
@@ -6,4 +14,3 @@ packages:
 web_server:
   port: 8080
   version: 2
-  ota: false

tests/components/web_server/test_ota.esp32-idf.yaml

@@ -1,8 +1,6 @@
-# Test configuration for ESP-IDF web server with OTA enabled
 esphome:
   name: test-web-server-ota-idf
 
-# Force ESP-IDF framework
 esp32:
   board: esp32dev
   framework:
@@ -15,17 +13,17 @@ packages:
 ota:
   - platform: esphome
     password: "test_ota_password"
+  - platform: web_server
 
-# Web server with OTA enabled
+# Web server configuration
 web_server:
   port: 8080
   version: 2
-  ota: true
   include_internal: true
 
 # Enable debug logging for OTA
 logger:
-  level: DEBUG
+  level: VERBOSE
   logs:
     web_server: VERBOSE
     web_server_idf: VERBOSE

tests/components/web_server/test_ota_disabled.esp32-idf.yaml

@@ -1,11 +1,18 @@
+esphome:
+  name: test-ws-ota-disabled-idf
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
 packages:
   device_base: !include common.yaml
 
-# OTA is configured but web_server OTA is disabled
+# OTA is configured but web_server OTA is NOT included
 ota:
   - platform: esphome
 
 web_server:
   port: 8080
   version: 2
-  ota: false